This invention relates generally to doors for mine stoppings and more particularly to latch mechanisms for such doors.
Stoppings are widely used in mines to block off the flow of air through some mine passageways. It is often desired that such stoppings be provided with a door for occasional access to the blocked-off passageway. A problem is encountered, however, in providing a door for a stopping because the floors of passages in mines often heave up or otherwise shift (sometimes referred to as a “convergence”), which may result in movement of the stopping and/or door frame. Such convergence may cause the door latch to become jammed or become unlatched, which allows the door to open for undesired flow of air through the doorway.
The doors disclosed in applicants' U.S. Pat. Nos. 4,082,331 and 6,032,986, incorporated herein by reference, address the aforementioned problem and offer generally satisfactory solutions. The present invention, however, represents an improvement with respect to the patented designs.